Health worker Xolisa Madikane tests blood for the HIV virus at a container lab next to the Gugulethu Community Health Clinic in Gugulethu on the outskirts of Cape Town, South Africa, Tuesday, July 21, 2009. South Africa launched a high-profile trial of an AIDS vaccine created by its own researchers Monday, a proud moment in a nation where government denial, neglect and unscientific responses have helped fuel the world's worst AIDS crisis. (AP Photo/Schalk van Zuydam)

Scientists are hoping to enroll 5,400 sexually active, HIV-negative men and women between the ages of 18 and 35 in the trial.

Once the participants are selected, they will receive five injections over the course of a year. Half will receive a placebo so researchers can measure whether the vaccine produced its desired effect, according to the Washington Post.

Gita Ramjee, the director of the HIV Prevention Research Unit at the Medical Research Council in Durban, South Africa, told the Washington Post scientists would be happy if the vaccine were even 45 to 50 percent effective because it would mean progress in a nation where more than 1,000 people are infected with the virus a day.

The new vaccine has been adapted to combat the specific HIV subtype in South Africa.

"Even a moderately effective vaccine would significantly decrease the burden of HIV disease over time in countries and populations with high rates of HIV infection, such as South Africa," said Anthony Fauci, director of the U.S. government's National Institute of Allergy and Infectious Diseases (NIAID).